Starting at 10 p.m., an estimated 186,000 drivers who use the connector road will have to take Katella east to southbound Los Alamitos Boulevard as crews begin work on rebuilding the road and adding an additional carpool lane as part of the $277 million West County Connector Project.

Drivers will be able to exit the 605 and take surface streets through Long Beach, Rossmoor and Seal Beach to reach the 405, or they can exit at Katella Avenue, go right on Los Alamitos Boulevard/Seal Beach Boulevard to get the the southbound 405.

Motorists can also exit at Spring Street in Long Beach and go left on Woodruff Avenue to reach the southbound 405.

At least one man is dreading the development.

“Since they’ve had the construction at the 22 (Freeway), it’s been a little bit difficult to get through, but for the most part it’s fairly clear,” said one commuter. “Starting tonight, it’s gonna be nasty!”

Overnight Sunday through Thursday, drivers were urged to exit the 605 at Willow, turn left on Studebaker, left on East Second Street/Westminster Avenue, then left at Seal Beach Boulevard to reach the 405 south.

The overall project, aimed at improving the flow of traffic on the two north-south freeways as well as the east-west Garden Grove (22) Freeway, is scheduled for completion in 2014.